Modular wheelchair frame

ABSTRACT

A modular wheelchair frame is provided having a first side frame and a second side frame. A collapsible structural assembly is releaseably connectable to the first and second side frames to space the first and second side frames apart. A rigid unitary structural assembly is also releaseably connectable to the first and second side frames to space the first and second side frames apart. The collapsible structural assembly and the rigid structural assembly are selectively interchangeable to convert the wheelchair frame between a rigid construction and a collapsible construction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of the filing date of U.S. Provisional Patent Application 60/509,490, “Modular Wheelchair Frame”, filed Oct. 8, 2003, the subject matter of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

The invention relates to the field of wheelchairs, and more particularly to manual wheelchairs that are convertible between various formations, such as a rigid construction and a foldable or collapsible construction.

Two common methods have been used in the design and production of manual wheelchairs. The most common is the folding cross brace wheelchair. This design utilizes a welded cross brace mechanism, allowing the wheelchair to fold similar to a director's chair (from side to side). The main advantage of this method is that the wheelchair can be easily folded by most users. The disadvantage of this design is low energy efficiency due to its loose construction since a part of the energy used to propel the wheelchair is transferred to the frame rather than the wheels.

A second popular design is the rigid frame wheelchair. In this design the cross brace mechanism is replaced with tubular crossbars welded to the side frames of the wheelchair. The advantage of this design is its energy efficiency. However, this wheelchair does not fold for easy storage or transportation.

For the majority of wheelchair users it is necessary to have both wheelchair designs. The folding wheelchair is more convenient for travel and indoor use, whereas the chair must be folded and stored. The rigid wheelchair is better suited for outdoors and a more active lifestyle. Unfortunately, it may not be economically feasible for most users to own both wheelchairs.

There have been attempts made to produce a wheel chair that is capable of being converted between the rigid design and the folding design. For example, U.S. Pat. No. 6,302,429 to Friedrich is directed to a convertible wheelchair. This design requires a vast array of different mounting locations, frame components, hardware, and brackets when converting from a folding design to a rigid design.

Also, traditional manual wheelchairs have back rests/supports that provide for height adjustment of the support. Typically, a set of holes is drilled within a telescoping tube at regularly spaced intervals. The support is adjusted according to the spacing of the holes; however, in some applications minute adjustments are required.

SUMMARY OF THE INVENTION

In a first aspect, the invention is a modular wheelchair frame comprising a first side frame and a second side frame. A collapsible structural assembly is releaseably connectable to the first and second side frames to space the first and second side frames apart. A rigid unitary structural assembly is also releaseably connectable to the first and second side frames to space the first and second side frames apart. The collapsible structural assembly and the rigid structural assembly are selectively interchangeable to convert the wheelchair frame between a rigid construction and a collapsible construction.

In another aspect, the invention is related to a wheelchair frame having a detachable assembly and a pair of side frame members. The detachable assembly includes a support structure having at least four ends, at least two upper members connected to a respective end of the support structure, and at least two lower members connected to a respective end of the support structure.

The side frame members are displaced from each other by the removable structure. Each one of the pair includes a first frame member, a second frame member, and a connecting member. The first frame member has a first end, a second end, and a least one support element fixedly attached to the first frame member that supports a respective one of the pair of upper members. The second frame member has a first end, a second end, and at least one bracket fixedly attached to the second frame member that is releasably attached a respective one of the pair of lower members. The connecting member has a first end connected to the first frame member and a second end connected to the second frame member and maintains the first and second frame members in substantially parallel alignment.

The detachable assembly may be foldable. The support structure can include at least two cross-support members connected at a pivot point. Each one of the cross-support members is connected to a respective one of the upper and lower members. The lower members can be hinged to a respective mounting component, which may releasably attach to the bracket of the second frame members.

The detachable assembly can also be rigid and made of aluminum. Each of the upper members may be releasably connected to a support element of a respective side frame. The frame may also include a leg rest assembly that is releasably attached to the first ends of the first and second frame members.

Each of the side frame members can include a back-support mounting tube disposed proximate to the second end of the first frame member. The back support mounting tubes can releasably attach a back support to the pair of side frame members.

In another aspect of the invention, a wheelchair back support is provided that can include a horizontal member and at least two stanchions. The horizontal member may have at least two tubular sections that extend substantially vertical from the horizontal member. Each of the tubular sections can have a first end and a second end configured to receive articles. A removable handle structure can be telescope within the first end of the tubular sections. The stanchions may each have a first end configured for attachment to the wheelchair frame and a second end having a portion configured to be received within the second end of a respective one of the tubular sections. The handle and stanchions may include a T-shaped groove along a portion thereof. The T-shaped groove and a plate cooperate to provide a telescoping feature for the back support. The stanchions can include a tilt adjustment mechanism. Also, the horizontal member can have a first section and a second section that can be attached to a bracket to facilitate the folding of the back support.

Another aspect of the invention is directed to a wheel chair frame that can includes a pair of side frame members spatially removed from one another. Each of the side frame members can include a first frame member, a second frame member and a connecting member the maintains the first frame member and the second frame member is substantially parallel alignment. At least one C-shaped support element can be attached to the first frame member. At least one bracket that may include a bore can be attached to the second frame member. The first frame member and the second frame member can also include a rear wheel mounting strip.

In another aspect of the invention, an assembly for use in a convertible wheelchair is provided. The assembly can include a support structure, at least two upper members attached to the support structure, and at least two lower members also attached to the support structure. Each of the upper and lower members is configured for releasable attachment to the wheelchair at fixed mounting locations.

It is also an aspect of the present invention that various combinations of the above-described aspects can be formed.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of illustrating the invention, there are shown in the drawings forms which are presently preferred; it being understood, that this invention is not limited to the precise arrangements and instrumentalities shown.

FIG. 1A is an isometric view of a wheelchair constructed according the principles of the present invention.

FIG. 1B is an exploded view of the wheelchair of FIG. 1A.

FIG. 2A is a perspective view of a first preferred embodiment of a side frame member of the wheelchair of FIG. 1A.

FIG. 2B is an end view of the side frame member of FIG. 2A.

FIG. 2C is perspective view of a second preferred embodiment of a side frame member in accordance with the present invention.

FIG. 3A is an isometric view of a rigid support structure constructed according to the principles of the present invention.

FIG. 3B is an end view of the rigid support structure of FIG. 3A.

FIG. 4A is an isometric view of a foldable support structure constructed according to the principles of the present invention.

FIG. 4B is an end view of the foldable support structure of FIG. 4A.

FIG. 5A is an isometric view of a back support constructed according the principles of the present invention.

FIG. 5B is an exploded view of the back support of FIG. 5A.

FIG. 6A is an embodiment of a back cane constructed according to the principles of the present invention.

FIG. 6B is an end view of the back cane of FIG. 6A.

FIG. 6C is a isometric view of an embodiment of a pivot structure that is attached to the back cane of FIG. 6A.

FIG. 7 is an isometric view of a leg rest support constructed according to the principles of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

In the drawings, in which like numerals indicate like elements, there is shown a wheelchair constructed according to the principles of the invention, a side frame member, both rigid and foldable detachable structures, a back support, and a leg rest for use with the modular wheelchair of the present invention.

With reference to FIGS. 1A and 1B, a wheelchair 10 constructed in accordance with the principles of the present invention includes a pair of side frame members 14A, 14B (referred to generally as side frame members 14), a detachable assembly 18, a back support 22, a pair of arm rests 24, a pair of leg rest assemblies 26A, 26B (referred to generally as leg rest assemblies 26), a foot rest 30, a seat web 32, a pair of front casters 34A, 34B, and a pair of rear wheels 38A, 38B that are mounted to a respective mounting plate 42.

With reference to FIGS. 2A and 2B, the side frame members 14 include a first frame member 46, a second frame member 50, and a connecting member 54. The first frame member 46 has a first end 58, a second end 62, a pair of support elements 66A, 66B (referred to generally as support element 66), a rear wheel upper mounting strip 70, and a back support mounting tube 74. The first frame member 46 can be constructed of round tubing or the first frame member can be solid. In a preferred embodiment, the first frame member 46 is a piece of round aluminum tubing having an outside diameter of approximately nineteen millimeters. Alternatively, square tubing or tubing of other shapes and materials can be used.

The first end 58 and the second end 62 of the first frame member 46 are open and configured to receive and removably attach an end of another component of the wheelchair 10 to the side frame member 14. For example, first end 58 can receive an end of the leg rest assembly 26. The second end 62 can receive an end of the arm rest 24 and releasably attach the arm rest 24 to the first frame member 46 by receiving a pin or other attachment mechanism through a bore 78. Alternatively, a cap (not shown) can be placed in either of the first end 58 or the second end 62 when being transported to protect the ends from becoming damaged. The tubular design facilitates the break down of the wheelchair and also allows for customization of the wheelchair by allowing pieces to be added and removed from the ends of the first frame member 46.

The support elements 66 are fixedly attached to the first frame member 46. That is, the location of the support elements 66 does not change when converting the wheelchair 10 from a rigid style to a foldable style. This reduces the complexity and the amount of the mounting hardware required to perform the conversion. The support elements 66 are configured to receive a portion of the detachable assembly 18, which is described in more detail below. The support elements 66 can be a semi-circular shape (i.e., C-shaped) and have a bore 82 configured to receive an attachment mechanism. As shown, there are multiple support elements 66; however, in various embodiments there may be only a single support element 66.

The rear wheel upper mounting strip 70 facilitates the attachment of the rear wheel 38 via the mounting plate 42. The mounting strip 70 is disposed proximate to the second end 62 and extends towards the first end 58. A plurality of bores 86 allow for the adjustment of the position of the rear wheel 38. The mounting strip 70 can be constructed of the same material as the first frame member 46 (e.g., aluminum) or of a different material (e.g., steel).

The back support mounting tube 74 allows the back support 22 to be releasably attached to the side frame member 14 via the bores 90. The back support mounting tube 74 is disposed proximate to the second end 62 and extends substantially perpendicular from the first frame member 46. The shape of the back support mounting tube 74 is complementary to an end of the back support 22 and can be different than the shape of the first frame member 46.

The second frame member 50 has a first end 94, a second end 98, a pair of brackets 102A, 102B (referred to generally as brackets 102), and a rear wheel lower mounting strip 106. The second frame member 50 can also be a constructed of round tubing or the second frame member 50 can solid. In a preferred embodiment, the second frame member 50 is a piece of round aluminum tubing having an outside diameter of approximately nineteen millimeters. Alternatively, square tubing or other shaped tubing of various materials can be used. The shapes of the first frame member 46 and the second frame member 50 can be substantially similar or different.

The first end 94 and the second end 98 of the second frame member 50 are open and configured to receive and removably attach an end of another component of the wheelchair 10 to the side frame member 14. For example, the first end 94 can receive an end of the leg rest assembly 26 and releasably attach the leg rest assembly 26 to the second frame member 50 via the bores 110. Alternatively, a cap (not shown) can be placed in either of the first end 94 or the second end 98 when being transported to protect the ends from being damaged.

The brackets 102 are fixedly attached to the second frame member 50. That is, the location of the brackets 102 does not change when converting the wheelchair 10 from a rigid style to a foldable style. This reduces the complexity and the amount of the mounting hardware required to perform the conversion. The brackets 102 are configured to mate with a portion of the detachable assembly 18, which is described in more detail below. The brackets 102 have a bore 114 configured to receive an attachment mechanism.

The rear wheel lower mounting strip 106 facilitates the attachment of the rear wheel 38 via the mounting plate 42. The mounting strip 106 is disposed proximate to the second end 98 and extends towards the first end 94. A plurality of bores 118 allow for the adjustment of the position of the rear wheel 38.

With reference now to FIG. 2C, a second embodiment of a rear wheel mounting plate 42′ is adapted for use in conjunction with a second embodiment of side frame members 14′. The second embodiment rear wheel mounting plate 42′ is generally L-shaped, and has a first end telescopically received within a second embodiment second frame member 50′. A second end of the second embodiment mounting plate 42′ is provided with holes adapted to mate with bores 86, allowing one or more fasteners (not shown) to connect the second embodiment mounting plate 42′ to the mounting strip 70. In this second embodiment side frame member 14′, the rear wheel lower mounting strip 106 is eliminated, and replaced by a plurality of holes 118′ drilled in the second embodiment second frame member 50′. The mounting plate 42′ may be connected to the second frame member 50′ by installing a fastener through a hole 118′ and a mating hole in mounting plate 42′.

The second embodiment rear wheel mounting plate 42′ further comprises a plurality of mounting holes wherein one of the rear wheels 38 of the wheelchair 10 may be adjustably connected to the second embodiment rear wheel mounting plate 42′ by a fastener (not illustrated) installed in one of the plurality of mounting holes. The second embodiment rear wheel mounting plate 42′ thus provides both wheel height adjustment along with longitudinal adjustment of the rear wheels 38 relative to a remainder of the wheelchair 10.

Other structural and functional features of the second embodiment side frame members 14′ are similar to corresponding features of the first embodiment side frame members 14. In particular, the structure and function of the first frame member 46, support elements 66, back support mounting tube 74 and brackets 102 are similar in both the first and second embodiment side frame members 14 and 14′.

It will be recognized that alternatively the second embodiment second frame member 50′ could be telescopically received within the second embodiment rear wheel mounting plate 42′.

With reference to FIGS. 3A and 3B, in one embodiment the detachable assembly 18 is rigid. That is, the detachable assembly 18 is not foldable. The detachable assembly 18 includes a support structure 122 that has ends 126A, 126B, 126C, . . . 126H (referred to generally as ends 126), two upper members 130A, 130B (referred to generally as upper members 130) attached to a respective end 126, and two lower members 134A, 134B (referred to generally as lower members 134) also attached to a respective end 126. Both the upper members 130 and lower members 134 can be tubular or solid.

In one embodiment, the support structure 122 includes a plurality of V-shaped solid or tubular supports 138. Each of the V-shaped supports 138 includes a first end, an apex 142, and a second end. The apex 142 of each of the V-shaped supports 138 is attached to the apex 142 of an opposing V-shaped supports 138. The first end of a first V-shaped supports 138 is the end 126A of the support structure 122. The second end of the same V-shaped support 138 is the end 126C of the support structure 122. The first end of the opposing V-shaped support 138 is the end 126B of the support structure 122, and the second end is the end 126D of the support structure 122. In an alternate embodiment (not illustrated), the V-shaped supports are rotated substantially 90°. The apexes 142 of two rotated V-shaped supports 138 are connected to a respective end of a substantially linear tubular or solid member. The resulting structure resembles a bent I-shape, wherein the linear member is substantially parallel to the ground.

The upper members 130 are attached to a respective end 126 of the support structure 122. The upper members 130 are shaped to be received by the support elements 66 of the side frame members 14. The upper members 130 can include a plurality of bores 146 and an inner extension tube 150. A respective bore 146 can be aligned with the bore 82 of the support element 66. A quick release attachment mechanism (i.e., a fastener) such as a pin can be inserted into through the bore to releasably attach the upper member 130 to the support element 66. The inner extension tube 150 telescopes from within the upper member 130 to provide additional length to the upper member 130. Additionally, the upper members 130 support the seat web 32 in which the user of the wheelchair 10 sits.

The lower members 134 are also attached to a respective end 126 of the support structure 122. The lower members 134 have first ends and second ends that are configured to be attached to the brackets 102 of the side frame members 14. In one embodiment, the first and second ends include a threaded bore which receives a screw that passes through the bore 114 of the bracket 102. In an alternate embodiment, the ends are configured to receive a quick-release attachment mechanism such as pin.

In order to remove the detachable assembly 18 from the side frame members 14, the attachment mechanisms that attach the upper members 130 to the support elements 66 and the lower members 134 to the brackets 102 are removed. Once removed, the detachable assembly 18 can be replaced with another detachable assembly 18′. For example, the detachable assembly 18′ can be a foldable type structure as shown in FIGS. 4A and 4B.

The detachable assembly 18′ includes a support structure 122′ that has ends 126A′, 126B′, 126C′, . . . 126H′ (referred to generally as ends 126′), two upper members 130A′, 130B′ (referred to generally as upper members 130′) attached to a respective end 126′, and two lower members 134A′, 134B′ (referred to generally as lower members 134′) also attached to a respective end 126′.

In this embodiment, the support structure 122′ facilitates the folding of the wheelchair 10 for easy transportation. The support structure 122′ includes a plurality of solid or tubular supports 138′. Each of the supports 138′ includes a first end and a second end. A pair of the supports 138′ is attached at a pivot point 154 by a pivot pin or the like. The first end of one of the supports 138′ is the end 126A′ of the support structure 122′. The second end of the same support 138′ is the end 126D′ of the support structure 122′. The first end of the other support 138′ is the end 126C′ of the support structure 122′, and the second end is the end 126B′ of the support structure 122′. As such, the supports 138′ form an X-shape that is foldable about the pivot point 154.

The upper members 130′ are attached to a respective end 126′ of the support structure 122′. The upper members 130′ are shaped to be received by the support elements 66 of the side frame members 14. The upper members 130′ can include a plurality of bores 146′ and an inner extension tube 150′. A respective bore 146′ can be aligned with the bore 82 of the support element 66. A quick-release attachment mechanism (i.e., a fastener) such as a pin can be inserted into through the bore to releasably attach the upper member 130′ to the support element 66. The inner extension tube 150′ telescopes from within the upper member 130′ to provide additional length to the upper member 130′. Additionally, the upper members 130′ support the seat web 32 in which the user of the wheelchair 10 sits.

The lower members 134′ are also attached to a respective end 126′ of the support structure 122′. The lower members 134′ have first ends and second ends which are configured to be attached to the brackets 102 of the side frame members 14. In one embodiment, the first and second ends include a threaded bore which receives a screw that passes through the bore 114 of the bracket 102. In an alternate embodiment, the ends are configured to receive a quick-release attachment mechanism such as pin.

With reference to FIGS. 5A and 5B, the back support 22 includes a horizontal member 160, a pair of removable push handles 164, and a pair of stanchions 168. The back support 22 can made of aluminum, although other materials such as steel and titanium can be used. A tubular section 172 is located at each end of the horizontal member 160. The tubular sections 172 extend vertically relative to the horizontal member 160. Each of the tubular sections 172 has a first end 176 configured to receive one of the push handles 164 and a second end 180 configured to receive one of the stanchions 168. Each of the tubular sections 172 also includes at least one bore 184 at each of the first end 176 and the second end 180. In one embodiment an adjustment knob 188 is threaded through the bore 184 of the first end 176 and attached to a plate or a shaped nut (neither shown).

In one embodiment, the horizontal member 160 is a two section structure that facilitates folding of the back support 22. Each section 160′ has an end that is attached to a respective tubular section 172 as described above and another end 162′ that is capped off. For example, a dome cap can be inserted into the end 162′ of the section. The two capped ends of the sections are placed in contact with each other and secured in place by a bracket or bar hinge 166. The bar hinge 166 is attached to each of the sections 160′ by screws or other quick release fasteners.

The removable handles 164 include a generally T-shaped groove 192 that extends from a first end 196 to a second end 200 of the handle 164. The first end 176 of the tubular section 172 receives the second end 200 of the handle 164. The groove 192 receives the plate that is within the tubular section 172. Although described as having a generally T-shape, the groove 192 can have other shapes as well. The second end 200 telescopes within the tubular section 172. Turning the adjustment knob 188 moves the plate into contact with groove 192 and fixes the height of the handle. An infinite number of height adjustments of the handles 164 are achievable with the plate and groove design of the present invention.

With reference to FIGS. 6A, 6B, and 6C, the stanchions 168 include a back cane section 204 and a tilt adjustment mechanism 208. Similar to the handles 164, the back cane section 204 includes a generally T-shaped groove 212 that extends from a first end 216 to a second end 220. Also, the back cane section 204 includes a plurality of bores 222 that are configured to receive an attachment mechanism such as a screw or the like. The second end 180 of the tubular section 172 receives the first end 216 of the back cane section 204. The first end 216 telescopes within the tubular section 172 and controls the overall height of the back support 22. Screws or other attachment means are inserted through the bores 184 of the second end 180 of the tubular section 160 and through a respective bore 222 of the back cane 204. In another embodiment, a shaped nut is disposed within the groove 212. An adjustment knob is used to set the height of the back support 22 forcing the plate into contact with groove 212.

The tilt adjustment mechanism 208 includes a bottom portion 224, a top portion 228, and a pivot section 232. The bottom portion 224 mates to a respective back support mount 74 of the side frame member 14 via a set of threaded bores 236. A screw or another similar fastener is inserted through bore 90 of the back support mount 74 and through bore 236 of the bottom portion 224 of the tilt adjustment mechanism 208. The back cane 204 is mated with the top portion 228 via the bores 222 of the back cane 204. A screw is inserted through a respective bore 222 and received by a bore 240 of the top portion 224. The angle of the back 204 is controlled by the pivot section 232. A part of the top portion 228 is inserted into the pivot section 232 and attached to the pivot section such that the desired angle of the back cane 204 is achieved.

With reference to FIG. 7, a second embodiment leg rest assembly 26′ includes an upper attachment member 244, a lower attachment member 248, a joining member 252 and a foot rest attachment member 256. The lower attachment member 248 is connected to the upper attachment member 244 via the joining member 252. The first end 58 of the first frame member 46 receives an end 260 of the upper attachment member 244. The first end 94 of the second frame member 50 receives an end 264 of the lower attachment member 248. Both the upper attachment member 244 and the lower attachment member 248 are releasably attached to the side frame member 14. The foot rest attachment member 256 has a first end 268 proximate to the upper attachment member 244 and a second end 272. The first end 268 is pivotally attached to the joining member 252. The foot rest attachment member 256 can swing through an angle of about 70°. The second end 272 is configured to receive a foot rest (not shown). Although a 70° swinging leg rest is illustrated, other conventional leg rest supports could be alternatively used. For example, a 1 inch or 2 inch tapered leg rest, an 80° rigid leg rest, a 1 or 2 inch offset leg rest, or a rigid leg rest could be substituted.

As noted above, a variety of modifications to the embodiments described will be apparent to those skilled in the art from the disclosure provided herein. Thus, the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification, as indicating the scope of the invention. 

1. A modular wheelchair frame comprising: a first side frame; a second side frame; a collapsible structural assembly releaseably connectable to the first and second side frames to space the first and second side frames apart; and a rigid unitary structural assembly releaseably connectable to the first and second side frames to space the first and second side frames apart, wherein the collapsible structural assembly and the rigid structural assembly are selectively interchangeable to convert the wheelchair frame between a collapsible construction and a rigid construction.
 2. The modular wheelchair frame of claim 1, the first and second side frames each including a first structural tube member and a second structural tube member, wherein the rigid unitary structural assembly is connectable to the first and second structural tube members of both the first and second side frames.
 3. The modular wheelchair frame of claim 1, wherein the rigid unitary structural assembly connects to the first side frame at no fewer than two connections and connects to the second side frame at no fewer than two connections.
 4. The modular wheelchair frame of claim 3, wherein the rigid unitary structural assembly connects to the first side frame at four connections and connects to the second side frame at four connections.
 5. A wheelchair comprising: a detachable support assembly comprising: a support structure having at least four ends, at least two upper members each connected to one of the at least four ends, and at least two lower members each connected to one of the at least four ends; and a pair of side frame members spaced from one another by the detachable assembly, each of the pair comprising: a first frame member having a first end, a second end, and at least one support element fixedly attached to the first frame member configured to support one of the at least two upper members, a second frame member having a first end, a second end, and at least one bracket fixedly attached to the second frame member and configured for attachment to one of the at least two lower members, and a connecting member having a first end connected to the first frame member and a second end connected to the second frame member, the connecting member maintaining the first frame member and second frame member in substantially parallel alignment.
 6. The wheelchair of claim 5 further comprising a rear wheel support plate, an upper rear wheel mounting strip connected to the first frame member and a lower rear wheel mounting strip connected to the second frame member, wherein the rear wheel support plate is connectable to the upper and lower rear wheel mounting strips.
 7. The wheelchair of claim 5 further comprising a rear wheel mounting plate and an upper rear wheel mounting strip connected to the first frame member, wherein the rear wheel mounting plate is connectable to the upper rear wheel mounting strip and is telescopically connectable to the second frame member.
 8. The wheelchair of claim 7, the rear wheel mounting plate further comprising a plurality of mounting holes wherein a rear wheel of the wheelchair may be adjustably connected to the rear wheel mounting plate.
 9. The wheelchair of claim 5 wherein the detachable assembly is foldable.
 10. The wheelchair of claim 9 wherein the support structure further comprises at least two cross-support members connected at a pivot point, each of the at least two cross-support members connected to one of the at least two upper members and one of the at least two lower members.
 11. The wheelchair of claim 10 wherein each of the at least two lower members is hinged to a mounting component, wherein each mounting component is releasably attached to the bracket of one of the pair of the second frame members.
 12. The wheelchair of claim 5 wherein the detachable assembly is rigid.
 13. The wheelchair of claim 5 wherein each of the at least two upper members is releasably attached to the support element of one of the pair of the first frame members.
 14. The wheelchair of claim 5 further comprising a leg rest assembly releasably attached to the first end of one of the pair of the first frame members and the first end of one of the pair of the second frame members.
 15. The wheelchair of claim 5 wherein each of the pair of the first frame members further comprises a back-support mounting tube disposed proximate to the second end extending substantially perpendicular therefrom.
 16. The wheelchair of claim 15 further comprising a back support releasably attached to each of the pair of side frame members via the back-support mounting tube.
 17. The wheelchair of claim 16 wherein the back support comprises a horizontal member having at least two tubular sections extending substantially perpendicular from the horizontal member, each of the tubular sections having a first end and a second end, and at least two stanchions each having a first end releasably attached to one of the pair of side frame members and a second end having a portion configured to be received within the second end of one of the at least two tubular sections.
 18. The wheelchair of claim 17 further comprising a push handle releasably attached to the first end of one of the at least two tubular sections, such that the push handle telescopes within the first end.
 19. The wheelchair of claim 18 wherein the push handle comprises a T-shaped groove therein.
 20. The wheelchair of claim 17 wherein the first end of each of the at least two stanchions comprises a tilt adjustment mechanism.
 21. The wheelchair of claim 17 further comprising a leg rest assembly releasably attached to the first end of one of the pair of the first frame members and the first end of one of the pair of the second frame members.
 22. A wheelchair back support comprising: a horizontal member a having at least two tubular sections extending substantially perpendicular therefrom, each of the tubular sections having a first end and a second end; and at least two stanchions each having a first end configured for attachment to a wheelchair frame and a second end having a portion configured to be received within the second end of one of the at least two tubular sections.
 23. The back support of claim 22 further comprising a push handle releasably attached to the first end of one of the at least two tubular sections.
 24. The back support of claim 22 wherein the push handle comprises a T-shaped groove therein.
 25. The back support of claim 24 wherein the push handle telescopes within the first end of one of the at least two tubular sections.
 26. The back support of claim 22 wherein the at least two stanchions comprise a T-shaped groove along a portion thereof.
 27. The back support of claim 22 wherein the first end of each of the at least two stanchions comprises a tilt adjustment mechanism.
 28. The back support of claim 22 wherein the horizontal member comprises a first section and a second section, wherein the first section and second section are attached to a bracket to facilitate the folding of the back support.
 29. A wheelchair frame comprising: a pair of side frame members spaced from one another, each of the pair comprising: a first frame member having a first end and a second end, at least one support element attached to the first frame member, a second frame member having a first end and a second end, at least one bracket attached to the second frame member, and a connecting member having a first end connected to the first frame member and a second end connected to the second frame member, the connecting member maintaining the first frame member and second frame member in substantially parallel alignment.
 30. The wheelchair frame of claim 29 wherein the at least one support element is C-shaped.
 31. The wheelchair frame of claim 30 wherein the at least one support element comprises a bore.
 32. The wheelchair frame of claim 29 wherein the at least one bracket comprises a bore.
 33. The wheelchair frame of claim 29 wherein the first frame member and the second frame member each further comprise a rear wheel mounting strip.
 34. The wheelchair frame of claim 29 further comprising an axle plate support member connectable to the first frame member and the second frame member.
 35. The wheelchair of claim 29 further comprising a rear wheel mounting plate and an upper rear wheel mounting strip connected to the first frame member, wherein the rear wheel mounting plate is connectable to the upper rear wheel mounting strip and is telescopically connectable to the second frame member.
 36. The wheelchair of claim 35, the rear wheel mounting plate further comprising a plurality of mounting holes wherein a rear wheel of the wheelchair may be adjustably connected to the rear wheel mounting plate by a fastener installed in one of the plurality of mounting holes.
 37. An assembly for use with a convertible wheelchair having at least one front caster, a pair of rear wheels, and a frame having fixed mounting points, the assembly comprising: a support structure having at least four ends; at least two upper members each connected to one of the least four ends; and at least two lower members each connected to one of the least four ends, wherein the at least two upper members and the at least two lower members are configured for releasable attachment to the fixed mounting points.
 38. The assembly of claim 37 wherein the assembly is foldable.
 39. The assembly of claim 38 wherein the support structure further comprises at least two cross-support members connected at a pivot point, each one of the cross-support members connected to one of the at least two upper members and one of the at least two lower members.
 40. The assembly of claim 37 wherein each one of the at least two lower members is hinged to a mounting component.
 41. The assembly of claim 37 wherein the assembly is rigid. 